Manufacture of iron and steel and products obtained



Patented July 13, 1954 UNITED STATES ATENT OFFICE MANUFACTURE OF IRON AND STEEL AND PRODUCTS OBTAINED ration of Delaware No Drawing. Application October 31, 1951, Serial No. 254,193

29 Claims. 1

The invention relates to a method for the production of iron and steel and to the products obtained thereby. More particularly, it pertains to the production of stainless steels and includes correlated improvements and discoveries whereby the properties of iron and steel are decidedly improved.

Further, the procedure may be employed with killed steel of alloy or or carbon grades, and the steel may be manufactured by conventional methods.

Steels, in the course of their manufacture adsorb certain undesirable gases and substances which may impart poor engineering properties and may make the material diificult to shape or work.

A principal object of the invention is to provide a method whereby the foregoing disadvantages may be substantially wholly obviated.

A further object of the invention is to provide a method accordance with which an iron and steel may be produced as a fine grain product, having distinctive corrosion and oxidation resistance, and high impact values at room and at low temperatures.

Another object of the invention is to provide a process for the manufacture of a steel having a relatively lowered sulphur content.

A particular object of the invention is the provision of a method whereby the foregoing are achieved, and a product, namely an-ir0n or a steel of enhanced properties, is obtained through the utilization of a composition containing a rare earth oxide, preferably a plurality of the oxides, such as an ore or a concentrate thereof, with cerium oxide desirably being present in a preponderant amount, and a reducing agent therefor. Furthermore, the composition may contain a suitable compound serving as a source of oxygen such as a nitrate, e. g. sodium nitrate, potassium nitrate, and the like. Moreover, it will be understood that the expression rare earth oxide as used herein includes other suitable compounds of the rare earth metals such as carbonate, chloride, and. silicide.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

For the production of a steel which is highly resistant to corrosion and oxidation, there are two generally accepted methods.

One method utilizes one or more of a number of commonly accepted alloys, and usually a minimum of 12% is employed. These alloys frequently contain a member of the group consisting of molybdenum, chromium, tungsten, nickel, columbium, cobalt, tantalum, titanium and zirconium with varying amounts of silicon, copper, aluminum and manganese.

The second method uses the minimum amount of those metals and produces a grain in which the interstitial spaces are reduced in size and, thus, reduces the opportunity for corrosive and oxidation agents to attack the steel.

In view of the fact that the alloys which are usually employed in producing heat resisting and stainless steels are in great demand and as such are hard to obtain at all times, we decided to attempt to improve these two types by producing a fine grain in the steel and to do this the molten steel has been treated with a composition composed essentially of oxides of the rare earth group or a group of rare earth oxides and a reducing agent therefor.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the iron or steel possessing the features and properties, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

In the practice of the invention, the properties of iron and steel, especially of stainless steels of high alloy type, such as the austenitic type and the chrome type, e. g. 19% chromium, and hard surfacing types as 3.5% nickel, 3% chromium, 7% molybdenum and 1% boron, are decidedly improved by the addition of an appropriate amount of a composition containing a rare earth oxide, either singly or in compatible combination, and a reducing agent therefor to a melt, that is to the liquid iron or steel. Suitably the rare earth oxide and the reducing agent are of relatively fine size and intimately admixed, and may be in the form of a briquette.

More especially, the procedure comprises preparing an iron containing melt, adding metallics, which may contain chromium, manganese, molybdenum, nickel, tungsten, columbium, cobalt, tantalum, titanium, zirconium and silicon,

thereto during furnacing and then deoxidizing,

utilizing e. g. ferro silicon, calcium, silicon, ferro manganese and the like, with the addition of, and in conjunction with, the composition which, more particularly, contains a plurality of rare earth oxides and a reducing agent therefor. The reducing agent may be a member selected from the group consisting of calcium, aluminum, sodium, silicon, magnesium and boron and a boride, borane, and silicide of calcium, strontium, manganese, chromium, iron, magnesium, nickel, boron and cobalt. The oxide constituent and the reducing agent may be present in the relative proportions of about 1.0 art oxide and about 0.02 to about 1.0 part reducing agent suitably 1.0 part oxide and 0.3-0.7 part reducing agent, such as calcium, and 0.06-0.5, more particularly0.12, reducing agent such as calcium boride and calcium silicide. Additionally, when an oxygen source is also present in the composition it may be in the form of a nitrate such as the nitrates of sodium, potassium, calcium and magnesium, and in an amount from about 60% to 70% by weight of the reducing agent.

The addition of the composition may be effected at difierent phases of the melting and furnacing, and in a convenient and accepted manner. A suitable procedure is to add it to the ladle either before, during or after deoxidizers have been added, and desirably before the ladle is onehalf full, that is while the ladle is less than onehalf full. However, another and somewhat preferred procedure is to place it in the bottom of the ladle and cover over with a deoxidizer such as calcium silicide, or it may be placed in a thick walled pipe and the ends closed, and then placed in the bottom of the ladle where the liquid ferrous metal may be poured on top of it. Either method delays the action so that there will be suiiicient liquid metal to allow a proper reaction therewith.

Further, we have found that when from about 1 to about 5 pounds of the oxide composition have been added per ton of iron or steel, a very fine grain structure results. However, depending on the pouring temperature, the size of the mold, and the analysis desired, an amount of about 3 pounds of the oxide composition to the ton has given beneficial results.

Stainless steels, which sometimes are a nickelchrome combination, generally, large dendrites and these large dendrites cause the steel to break when any extra pressure is applied. However, when this class of steel is treated with the rare earth oxide composition, there is produced a fine grain structure so that it is possible entirely to by-pass a forging operation. Moreover, it may be rolled as any normal steel to billet size.

In the manufacture of these steels, the usual accepted good practice is employed and in addi tion to it, care is taken to see that the steel is properly deoxidized, that is, poured at a tern" perature which has been found to be lower than usual practice because of the fact that the treatment with the rare earth oxide-reducing agent composition seems to increase the fluidity of the treated metal.

Various quantities of the composition have been tried and found to be effective. However, when excessive amounts have been added, the steel has been found to be extremely dirty and as such offered low resistance to oxidation or corrosion. Our method makes efiicient use thereof and at the same time utilizes only a very small amount. We have definitely found that not more than as-cast, have about 4.5 pounds of the oxide composition per ton need be used provided that it is added to the melt as herein described and especially in the preferred manner.

As an illustrative embodiment of a manner in which the method may be carried out, the following examples are presented:

EXAMPLE 1 310 stainless A heat was made having the following approximate analysis expressed as percentages:

The power having been turned on, the following additions were made:

Pounds Burnt lime 800 Chrome silicon 800 Ferro silicon (75%) 420 After the charge had been melted and during furnacing, there were added:

Pounds Ferro chrome (0.06 C.) 6,508 Manganese (low carbon) 400 Nickel 1,841

Following adequate working of the heat, and the slag being in proper condition, approximately seven hours from charge to pour, 169 pounds of calcium silicon and 50 pounds of a composition containing rare earth oxide, calcium boride and sodium nitrate in the proportions of l:0.12:0.08 were added to the ladle. If desired the rate earth oxide composition may be introduced into the ladle and covered with the calcium silicon prior to pouring.

EXAMPLE 2 310 stainless A heat was made having the following approximate analysis expressed as percentages:

Carbon 0.11 Manganese 1.72 Sulphur 0.007 Phosphorus 0.02 Silicon 0.46 Nickel 20.7 Chromium 24.9 Copper 0.26 Rare earth metal 0.005 Remainder iron.

The charge consisted of:

Pounds Nickel (sinter) 2,000 Scrap (stainless) 29,200 Scrap (pit) 3,000 Turnings 3,600

The power having been turned on, the following additions were made:

Pounds Fluorspar 150 Burnt lime 2,400 Ferro silicon (fine) 2,625

When the charge had been melted there were added to the furnace:

Pounds Manganese (low carbon) 802 Chromium (low carbon) 6,000 Chromium (0.50 C.) 8,000 Nickel 1,800

EXAMPLE 3 Manganese molybdenum A heat was made having the following approximate analysis expressed. as percentages:

Carbon 0.28

Manganese 1.88 Sulphur 0.03 Phosphorus 0.011 Silicon 0.21

Molybdenum 0.46 Rare earth metal 0.005

Remainder iron.

The charge consisted of:

Pounds Scrap 4,400 Pig iron 4,300

The charge having melted there were added during furnacing:

Pounds Roll scale 8 Molybdenum trioxide 105 Spar 10 Ferro silicon (11%) 65 Ferro manganese (regular) 190 The heat having been adequately worked and the slag being in proper condition, there were added to the ladle:

Pounds Ferro manganese 98 Alsifer (a carbonless alloy of aluminum,

silicon and iron in the approximate respective percentages 20, 40 and 40) 26 Grainal 1'7 Calcium silicon 10 Rare earth oxide composition 12 The rare earth oxide composition contains rare earth oxide, calcium boride and sodium nitrate in the relative proportions of 1:0.12:0.08. The heat was tapped for pouring in the usual manner with the slag being held back.

EXAMPLE 4 Manganese molybdenum A heat was made having the following approximate analysis expressed as percentages:

Carbon 0.30 Manganese 1.92

Sulphur 0.026 Phosphorus 0.019 Silicon 0.24 Molybdenum 0.44 Rare earth metal 0.005 Remainder iron.

The charge consisted of:

Pounds Scrap 4,400 Pig iron 4,300

When the charge had melted and during furnacing, there were added:

Pounds Molybdenum trioxide 70 Spar 20 Scale 15 Ferro silicon 65 Ferro manganese 190 When the heat had been suitably worked and the slag being in proper condition, usually about seven hours from charge to pour, there were added to the ladle:

Pounds Ferro manganese 98 Alsifer 26 Grainal 17 Calcium silicon 12 Rare earth oxide composition 12 The rare earth oxide composition contained rare earth oxide, calcium silicide and sodium nitrate in the relative proportions of 1:0.5:0.08. The rare earth composition prior to pouring of the heat was placed in the bottom of the ladle and covered with the calcium silicon.

EXAMPLE 5 Manganese molybdenum A heat was made having the following approximate analysis expressed as percentages:

Carbon 0.31 Manganese 1.8 Sulphur 0.027 Phosphorus 0.014 Silicon 0.21 Molybdenum 0.44 Rare earth metal 0.005 Remainder iron.

The charge consisted of:

Pounds Scrap 4,250 Pig iron 4,500

Following melting of the charge there were added during furnacing:

Pounds Roll scale 10 Molybdenum trioxide 100 Ferro silicon (11%) 70 Ferro manganese (regular) Following adequate working of the heat and the slag being in proper condition, ordinarily about seven hours from charge to pour, there were added to the ladle:

Pounds Ferro manganese 85 Alsifer 25 Ferro boron 2.5 Calcium silicon 10 Rare earth oxide composition 12 The rare earth oxide composition contained a rare earth oxide and calcium boride in the rela-. tive proportions. 01110.12.

EXAMPLE 6 Manganese molybdenum- A heat was made having the following approximate analysis expressed as percentages:

Carbon 0.26 Manganese 1:72 Sulphur 0.029 Phosphorus 0.012 Silicon 0.24 Molybdenum 0.47 Rare earth meta1 0.005

Remainder iron.

The charge consisted of:

Pounds Scrap 4,700 Pig iron 4,000

Following melting down of the charge there were added during furnacing:

Pounds Roll scale 12. Molybdenum trioxide 105 Spar 10 Ferro silicon (11%) 65 Ferro manganese (regular) 190 When the heat had been properly worked with the slag being in suitable condition, desirably seven hours from charge to pour, there were added to the ladle during pouring:

Pounds Ferro manganese 90 Alsifer Ferro boron 2.25 Calcium silicon 10 Rare earth oxide composition 12 The rare earth oxide composition contained rare earth oxide and calcium silicide in the relative roportions of 1:0.5.

EXAMPLE 7 Manganese molybdenum A heat was made having the following approxi- Following melting down of the charge there were added during furnacing:

Pounds Roll scale l2 Molybdenum trioxide 100. Spar 5 Ferro silicon (11%) 65' Ferro manganese (regular) 185':

When the heat had been properly worked with the slag being in suitable condition, desirably seven hours from charge to pour, there were added to the ladle during pouring:

The rare earth oxide composition contained rare earth oxide, metallic calcium and sodium nitrate in the relative proportions of 1:0.7:0.08.

Grainal, included in several of the foregoing examples, is'an alloy containing aluminum, zirconium, titanium and boron of the following approximate percentage composition; aluminum 13.00; titanium 20.00; zirconium 4.00; manganese 8.00; boron 0.50; silicon 5.00, and the balance iron.

The method herein described for the production of iron and steel leads to the formation of a fine grain structure which enhances the resistance to corrosion. Since there is, at most, only a small amount of the oxide composition remaining in the treated metal, it is believed that this condition is due to the small space between the grains which results from the reduction of the original dendritic structure, and hence, ofiers less interstitial space for attack.

There is then produced ametal with a fine grain and with a reduced sulphur content. This. of course, attends usually only when the procedure is followed as described hereinabove in this application. The amounts to be used, as sugu gested above, depend upon the composition of the steel, but we have found that not more than about 4.5 pounds per ton of rare earth oxide composition need be employed and chemical analysis of'the finished steel shows a rare earth metal content not greater than 0.018%, expressed as cerium. When steel has been treated with the rare earth oxide-reducing agent composition, and a fine grain thus produced; the steel possesses decidely better resistance to corrosion and oxidation and, in addition, higher impact values at room and at low temperatures. These properties can be used to advantage; the first in stainless steel of various types, and the second in such applications as armor plate, gun steels, and alloy steels whose resistance to shock must be of the highest order.

The results show that there are several advantages which accrue to the user of the composition when employed in the manner described herein.

.Thus, .one may use a standard material and obtaindecided benefits due to its resistance to cor,- rosionzand oxidation. Further, the analysis may be varied sothat less of a scarce and costly alloy will be employed to obtain the. same results as .the same untreated material with a larger 1' For instance, a good pouring temperature for slag. reduces. such. action, and. this .may be -ac.-

complishedby theaddition of slag making materials such as dolomite, burnt lime, and the like. Among the advantages attending the use of the oxide-reducing agent composition are a reduction of the sulphur content and the obtention of a fine grain as cast. These occasion higher impact values at room and at low temperatures, and such values are especially important in those types of steel which must function properly and safely at low temperatures, e. g. those in the Arctic and Antarctic regions.

Furthermore, when molten ferrous material has been treated as herein described, a fine grain results and later certain definite improved physical and chemical characteristics are obtained. When steels are made in this way, it is highly desirable to make the steel so that this fine grain, as cast, persists. This is accomplished by casting at a relatively low temperature, and tapping or teeming as quickly as possible to solidfy the material.

We have observed that if, after treatment with the substance which endows it with these fine grain properties, the metal is allowed to remain in a liquid state for a long period of time, the fine grain gradually disappears and the resultant steel compares in almost every way, with an untreated steel. Moreover, when a melt is so treated and subsequently cast as a sand casting, whose solidification rate is very slow, a very small reduction in the grain size is obtained which indicates that retention for a long time after treatment in a liquid state allows the force which produces the fine grain to be dissipated and, hence, the fine grain qualities are not attained.

A distinctive characteristic of this treatment is that only a small amount is used, and this is such that analysis of the finished steel shows that the quantity added is no longer existent and that the quantity present is less than 0.018%, e. g. cerium. The rare earth metal content desirably may range from about 0.003% to 0.009%, and suitably will be about 0.005% This indicates that it is not the presence of an alloy which confers this fine grain property but rather an effect which is considered to induce nucleation.

It may be added, somewhat by way of recapitulation, that a steel, and particularly certain stainless varieties, having a tendency to solidify in large dendrites has a much smaller grain size ascast than the untreated metal. This finer grain size improves the rolling qualities, increases resistance to corrosion, and gives a relatively high impact value at low temperatures.

Since certain changes in carrying out the above process, and certain modifications in the product which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

l. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing, incorporating a composition containing a rare earth oxide and a reducing agent therefor, pouring and quick freezing.

2. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing with the addition, and in conjunction therewith, of a composition containing a rare earth oxide and a reducing agent therefor, pouring and quick freezing.

3. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing, incorporating a composition containing a plurality of rare earth oxides and a reducing agent therefor, pouring and quick freezing.

4. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing with the addition, and in conjunction therewith, of a composition containing a plurality of rare earth oxides, cerium oxide being present in a preponderant amount and a reducing agent therefor, pouring and quick freezing.

5. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing substantially completely, then adding a composition containing a plurality of rare earth oxides, cerium oxide being present in a preponderant amount and a reducing agent therefor, said composition being added in an amount not more than about 4.5 pounds per ton, pouring and quick freezing,

6 A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing, adding a composition containing a rare earth oxide and a reducing agent therefor, to the ladle, pouring and quick freezing.

7. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing, adding a composition containing a rare earth oxide and a reducing agent therefor, to the ladle during tapping, and while the ladle is less than one-half full, pouring and quick freezing.

8. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, introducing a composition containing a rare earth oxide and a reducing agent therefor, into the ladle covering said composition with a deoxidizing material and quick freezing, then tapping.

9. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing, incorporating a composition containing a rare earth oxide and a reducing agent therefor, selected from the group consisting of calcium, aluminum, sodium, silicon, magnesium and boron and a boride, borane and silicide of calcium, strontium, manganese, chromium, iron, magnesium, nickel, boron and cobalt, pouring and quick freezing.

10. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing, incorporating a composition containing a rare earth oxide and a reducing agent therefor, selected from the group consisting of calcium, aluminum, sodium, silicon, magnesium and boron, pouring and quick freezing.

11. A method for the production of iron and steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing, incorporating a composition containing a rare earth oxide and a reducing agent 'therefor, selected from the group consisting of a 'boride, borane and silicide'of calcium, strontium,

manganese, chromium, iron, magnesium, nickel, boron and cobalt, pouring and quick freezing.

1 A method for the production of iron and ,steel which comprises preparing an iron containing melt, adding metallics thereto during furnacing, deoxidizing, incorporating a composition containing a rare earthoxide and a reducing agent therefor, selected from the group consisting of calcium, aluminum, sodium, silicon, magnesium "and boron and a boride, borane and silicide of calcium; strontium, manganese, chromlum, iron, "magnesium, nickel, boronand cobalt, the oxide constituent and the reducing agent being present in the proportions ofabout 1.0 part oxide and :about 0.02 to about 1.0 part reducing agent, pour- "ingand quick freezing.

13. A method for the production or iron and steel which comprises preparing an iron contain- -ing melt, adding metallics containing chromium, molybdenum,

manganese, nickel and silicon thereto during furnacing, 'deoxidizing substantially completely then adding a composition containing a plurality of rare earth oxides, cerium oxide being present in a preponderant amount anda reducing agent tl1erefor,'selected from the group consisting of calcium, aluminum, sodium, -silicon, magnesium and boron and a boride, bo-

rane and silicide of calcium, strontium, manganese, chromium, iron, magnesium, nickel, boron and cobalt, the oxide constituent and the reducing agent being present in the proportions of about 1.0 part oxide and about 0.02 to about 1.0 part reducing agent, pouring and quick freezing. 14. A composition of matter consisting essentially of a rare earth oxide in intimate admixture with a reducing agent therefor said composition 'being for the production of iron-and steel and the oxide constituent and the reducing agent being present in the proportions of about 1.0 part oxide and about'0.02 to about 1.0'part reducing agent.

15. A composition of matter consisting essentially of a plurality of rare earth oxides in intimate admixture with a'reducing agent therefor 'said composition being for the production of iron said composition'beingforthe production of iron 'and steel and the oxide constituent and the reducin agent being present in the proportions of about 1.0 part oxide and about-0.02 to about 1.0 part reducing agent.

'17. A composition of matter consisting essen* tially of a rare earth oxide in intimate admixture with a reducing agent therefor, selected from the group consisting of calcium, aluminum, sodium,

"silicon, magnesium and boron and a boride, -borane and silicide of calcium, strontium, manganese, chromium, iron, magnesium, nickel,

"boron and cobalt, the oxide constituent and the reducing agent being present in the proportions "of about 1.0 part oxide and about 0.02 to about 1.0 part reducing agent, said composition being for the production of iron and steel.

l8. A composition of matter consisting essentia lly of a plurality of rare earth oxides, containing cerium oxide in a preponderant amount in intimate admixture with-a reducing agent thereits for, selected from the group consisting of calcium, aluminum, sodium, silicon, magnesium and boron and a boride, borane and silicide of calcium, strontium, manganese, chromium, iron, magnesium, nickel, boron and cobalt, the oxide constituent and the reducing agent being present in the proportions of about 1.0 part oxide and'about 0.06 to about 0.! part reducing agent, said composition being for the production of iron and steel.

19. A composition of matter consisting essen tially of a rare earth oxide in intimate admixture with a reducing agent therefor, selected from the group consistin of calcium, aluminum, sodium, silicon, magnesium and boron, the oxide constituent and the reducing agent bein present in the proportions of about 1.0 part oxide and about 0.3 to about 0.7 part reducing agent, said composition being for the production of iron and steel.

20. A composition of matter consisting essentially-of a rare earth oxide in intimate admixture with a reducing agent therefor, selected from the group consisting of a boride, borane and silicide of calcium, strontium, manganese, chromium,

; iron, magnesium, nickel, boron and cobalt, the

oxide constituent and the reducing agent being present in the proportions of about 1.0 part oxide and about 0.05 to about 0.5 part reducing agent,

" said composition being for the production of iron and steel.

21. A composition of matter consisting essentially of a rare earth oxide in intimate admixture with a reducing agent therefor, and a compound serving as an oxygen source, the oxide constituent and the reducing agent being present in the proportions of about 1.0 part oxide and about 0.02 to about 1.0 part reducing agent, and the oxygen source compound in an amount from about 60 to about 70% by weight of the reducing agent, said composition being for the production of iron and steel.

22. A composition of matter consisting essentially of a rare earth oxide in intimate admixture with a reducingagenttherefor and a member of the group consisting of sodium, potassium, calcium and magnesium nitrates, the oxide constituent and the reducing agent being present in the proportions of about 1.0 part oxide and about 0.02 to'about 1.0 part reducing agent, and the nitrate in an amount from about 60% to about 70% by Weight of the reducing agent, said composition being for the production of iron and steel.

23. An iron characterized by a fine grain structure, substantial freedom from dendrites, a relatively high impact value at low temperatures, capable of being directly rolled to billet size, and

having a content of rare earth metal not greater than 0.018%, expressed as cerium, said iron being produced by the method defined in claim 1.

24. A steel characterized by a fine grain structure, substantial freedom from dendrites, a relatively high impact value at low temperatures, capable of being directly rolled to billet size, and having a content of rare earth metal not greater than 0.018%, expressed as cerium, said steel being produced by the method defined in claim 3.

25. A stainless steel characterized by a fine grain structure, substantial freedom from dendrites, resistance to corrosion, a relatively high impact value at low temperatures, capable of beingdirectly rolled to billet size, and having a content of rare 'earth metal not greater than 0.018%, expressed as cerium, said steel being produced by the method defined inclaim 3.

.26. An ironcharacterized bya fine grainstructure, substantial freedom from dendrites, a relatively high impact value at low temperatures, capable of being directly rolled to billet size, and having a content of rare earth meta1 from about 0.003% to about 0.009%, expressed as cerium, said iron being: produced by the method defined in claim 1.

27. A stainless steel characterized by a fine grain structure, substantial freedom from dendrites, resistance to corrosion, a relatively high impact value at low temperatures, capable of being directly rolled to billet size, and having a content of rare earth metal from about 0.003% to about 0.009%, expressed as cerium, said steel being produced by the method defined in claim 4.

28. A stainless steel characterized by low sulphur content, a fine grain structure, substantial freedom from dendrites, resistance to corrosion, a relatively high impact value at low temperatures, capable of being directly rolled to billet size, and having a content of rare earth metal from about 0.003% to about 0.009%, expressed as cerium, said steel being produced by the method defined in claim 3.

29. A stainless steel characterized by low sulphur content, a fine grain structure, substantial freedom from dendrites, resistance to corrosion, a relatively high impact value at low temperatures, capable of being directly rolled to billet size, and having a content of rare earth metal of about 0.005%, expressed as cerium, said steel being produced by the method defined in claim 4.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,892,044 Elred et al Dec. 27, 1932 2,036,576 Hardy Apr. 7, 1936 2,194,965 Andrieux Mar. 26, 1940 2,249,336 Udy July 15, 1941 2,320,260 Browne May 25, 1943 2,325,314 Harbart et al July 27, 1943 2,334,870 Franks Nov. 23, 1943 2,346,382 Linz Apr. 11, 1944 2,355,627 Cadwell Aug. 15, 1944 2,350,717 Phelps Oct. 17, 1944 2,470,935 Linz May 24, 1949 FOREIGN PATENTS Number Country Date 20,884 Great Britain of 1905 11,606 Great Britain of 1907 388,948 France Dec. 27, 1943 OTHER REFERENCES Making, Shaping and Treating of Steel, 6th ed., page 575. Published in 1951 by the United States Steel Corp., Pittsburgh, Pa. 

1. A METHOD FOR THE PRODUCTION OF IRON AND STEEL WHICH COMPRISES PREPARING AN IRON CONTAINING MELT, ADDING METALLICS THERETO DURING FURNACING, DEOXIDIZING, INCORPORATING A COMPOSITON CONTAINING A RARE EARTH OXIDE AND A REDUCING AGENT THEREFOR, POURING AND QUICK FREEZING. 